<?php defined('BASEPATH') OR exit('No direct script access allowed');

// To disable UhOh! simply change IN_PRODUCTION to TRUE.
if ( ! defined('IN_PRODUCTION'))
{
	define('IN_PRODUCTION', FALSE);
}

/**
 * CodeIgniter UhOh!
 *
 * This is an extension on CI_Extensions that provides awesome error messages
 * with full backtraces and a view of the line with the error.  It is based
 * on Kohana v3 Error Handling.
 *
 * @package		CodeIgniter
 * @author		Dan Horrigan <http://dhorrigan.com>
 * @license		Apache License v2.0
 * @version		1.0
 */

/**
 * This file contains some functions originally from Kohana.  They have been modified
 * to work with CodeIgniter.  Here is the obligatory Kohana license info:
 *
 * @copyright  (c) 2008-2009 Kohana Team
 * @license	   http://kohanaphp.com/license
 */

/**
 * MY_Exceptions
 *
 * @subpackage	Exceptions
 */
class MY_Exceptions extends CI_Exceptions
{
	/**
	 * Some nice names for the error types
	 */
	public static $php_errors = array(
		E_ERROR				 => 'Fatal Error',
		E_USER_ERROR		 => 'User Error',
		E_PARSE				 => 'Parse Error',
		E_WARNING			 => 'Warning',
		E_USER_WARNING		 => 'User Warning',
		E_STRICT			 => 'Strict',
		E_NOTICE			 => 'Notice',
		E_RECOVERABLE_ERROR	 => 'Recoverable Error',
	);
	
	/**
	 * The Shutdown errors to show (all others will be ignored).
	 */
	public static $shutdown_errors = array(E_PARSE, E_ERROR, E_USER_ERROR, E_COMPILE_ERROR);
	
	/**
	 * Construct
	 *
	 * Sets the error handlers.
	 *
	 * @access	public
	 * @return	void
	 */
	public function __construct()
	{
		parent::__construct();
		
		// If we are in production, then lets dump out now.
		if (IN_PRODUCTION)
		{
			return;
		}
		
		//Set the Exception Handler
		set_exception_handler(array('MY_Exceptions', 'exception_handler'));

		// Set the Error Handler
		set_error_handler(array('MY_Exceptions', 'error_handler'));

		// Set the handler for shutdown to catch Parse errors
		register_shutdown_function(array('MY_Exceptions', 'shutdown_handler'));

		// This is a hack to set the default timezone if it isn't set. Not setting it causes issues.
		date_default_timezone_set(date_default_timezone_get());
	}

	/**
	 * Debug Path
	 *
	 * This makes nicer looking paths for the error output.
	 *
	 * @access	public
	 * @param	string	$file
	 * @return	string
	 */
	public static function debug_path($file)
	{
		if (strpos($file, APPPATH) === 0)
		{
			$file = 'APPPATH/'.substr($file, strlen(APPPATH));
		}
		elseif (strpos($file, SYSDIR) === 0)
		{
			$file = 'SYSDIR/'.substr($file, strlen(SYSDIR));
		}
		elseif (strpos($file, FCPATH) === 0)
		{
			$file = 'FCPATH/'.substr($file, strlen(FCPATH));
		}

		return $file;
	}
	
	/**
	 * Error Handler
	 *
	 * Converts all errors into ErrorExceptions. This handler
	 * respects error_reporting settings.
	 *
	 * @access	public
	 * @throws	ErrorException
	 * @return	bool
	 */
	public static function error_handler($code, $error, $file = NULL, $line = NULL)
	{
		if (error_reporting() & $code)
		{
			// This error is not suppressed by current error reporting settings
			// Convert the error into an ErrorException
			self::exception_handler(new ErrorException($error, $code, 0, $file, $line));
		}

		// Do not execute the PHP error handler
		return TRUE;
	}

	/**
	 * Exception Handler
	 *
	 * Displays the error message, source of the exception, and the stack trace of the error.
	 *
	 * @access	public
	 * @param	object	 exception object
	 * @return	boolean
	 */
	public static function exception_handler(Exception $e)
	{
		try
		{
			// Get the exception information
			$type	 = get_class($e);
			$code	= $e->getCode();
			$message = $e->getMessage();
			$file	 = $e->getFile();
			$line	 = $e->getLine();

			// Create a text version of the exception
			$error = self::exception_text($e);

			// Log the error message
			log_message('error', $error, TRUE);

			// Get the exception backtrace
			$trace = $e->getTrace();

			if ($e instanceof ErrorException)
			{
				if (isset(self::$php_errors[$code]))
				{
					// Use the human-readable error name
					$code = self::$php_errors[$code];
				}

				if (version_compare(PHP_VERSION, '5.3', '<'))
				{
					// Workaround for a bug in ErrorException::getTrace() that exists in
					// all PHP 5.2 versions. @see http://bugs.php.net/bug.php?id=45895
					for ($i = count($trace) - 1; $i > 0; --$i)
					{
						if (isset($trace[$i - 1]['args']))
						{
							// Re-position the args
							$trace[$i]['args'] = $trace[$i - 1]['args'];

							// Remove the args
							unset($trace[$i - 1]['args']);
						}
					}
				}
			}
			// Start an output buffer
			ob_start();

			// This will include the custom error file.
			require APPPATH . 'errors/error_php_custom.php';

			// Display the contents of the output buffer
			echo ob_get_clean();

			return TRUE;
		}
		catch (Exception $e)
		{
			// Clean the output buffer if one exists
			ob_get_level() and ob_clean();

			// Display the exception text
			echo self::exception_text($e), "\n";

			// Exit with an error status
			exit(1);
		}
	}
	
	/**
	 * Shutdown Handler
	 *
	 * Catches errors that are not caught by the error handler, such as E_PARSE.
	 *
	 * @access	public
	 * @return	void
	 */
	public static function shutdown_handler()
	{
		$error = error_get_last();
		if ($error = error_get_last() AND in_array($error['type'], self::$shutdown_errors))
		{
			// Clean the output buffer
			ob_get_level() and ob_clean();

			// Fake an exception for nice debugging
			self::exception_handler(new ErrorException($error['message'], $error['type'], 0, $error['file'], $error['line']));

			// Shutdown now to avoid a "death loop"
			exit(1);
		}
	}
	
	/**
	 * Exception Text
	 *
	 * Makes a nicer looking, 1 line extension.
	 *
	 * @access	public
	 * @param	object	Exception
	 * @return	string
	 */
	public static function exception_text(Exception $e)
	{
		return sprintf('%s [ %s ]: %s ~ %s [ %d ]',
			get_class($e), $e->getCode(), strip_tags($e->getMessage()), $e->getFile(), $e->getLine());
	}
	
	/**
	 * Debug Source
	 *
	 * Returns an HTML string, highlighting a specific line of a file, with some
	 * number of lines padded above and below.
	 *
	 * @access	public
	 * @param	string	 file to open
	 * @param	integer	 line number to highlight
	 * @param	integer	 number of padding lines
	 * @return	string	 source of file
	 * @return	FALSE	 file is unreadable
	 */
	public static function debug_source($file, $line_number, $padding = 5)
	{
		if ( ! $file OR ! is_readable($file))
		{
			// Continuing will cause errors
			return FALSE;
		}

		// Open the file and set the line position
		$file = fopen($file, 'r');
		$line = 0;

		// Set the reading range
		$range = array('start' => $line_number - $padding, 'end' => $line_number + $padding);

		// Set the zero-padding amount for line numbers
		$format = '% '.strlen($range['end']).'d';

		$source = '';
		while (($row = fgets($file)) !== FALSE)
		{
			// Increment the line number
			if (++$line > $range['end'])
				break;

			if ($line >= $range['start'])
			{
				// Make the row safe for output
				$row = htmlspecialchars($row, ENT_NOQUOTES);

				// Trim whitespace and sanitize the row
				$row = '<span class="number">'.sprintf($format, $line).'</span> '.$row;

				if ($line === $line_number)
				{
					// Apply highlighting to this row
					$row = '<span class="line highlight">'.$row.'</span>';
				}
				else
				{
					$row = '<span class="line">'.$row.'</span>';
				}

				// Add to the captured source
				$source .= $row;
			}
		}

		// Close the file
		fclose($file);

		return '<pre class="source"><code>'.$source.'</code></pre>';
	}
	
	/**
	 * Trace
	 *
	 * Returns an array of HTML strings that represent each step in the backtrace.
	 *
	 * @access	public
	 * @param	string	path to debug
	 * @return	string
	 */
	public static function trace(array $trace = NULL)
	{
		if ($trace === NULL)
		{
			// Start a new trace
			$trace = debug_backtrace();
		}

		// Non-standard function calls
		$statements = array('include', 'include_once', 'require', 'require_once');

		$output = array();
		foreach ($trace as $step)
		{
			if ( ! isset($step['function']))
			{
				// Invalid trace step
				continue;
			}

			if (isset($step['file']) AND isset($step['line']))
			{
				// Include the source of this step
				$source = self::debug_source($step['file'], $step['line']);
			}

			if (isset($step['file']))
			{
				$file = $step['file'];

				if (isset($step['line']))
				{
					$line = $step['line'];
				}
			}

			// function()
			$function = $step['function'];

			if (in_array($step['function'], $statements))
			{
				if (empty($step['args']))
				{
					// No arguments
					$args = array();
				}
				else
				{
					// Sanitize the file path
					$args = array($step['args'][0]);
				}
			}
			elseif (isset($step['args']))
			{
				if (strpos($step['function'], '{closure}') !== FALSE)
				{
					// Introspection on closures in a stack trace is impossible
					$params = NULL;
				}
				else
				{
					if (isset($step['class']))
					{
						if (method_exists($step['class'], $step['function']))
						{
							$reflection = new ReflectionMethod($step['class'], $step['function']);
						}
						else
						{
							$reflection = new ReflectionMethod($step['class'], '__call');
						}
					}
					else
					{
						$reflection = new ReflectionFunction($step['function']);
					}

					// Get the function parameters
					$params = $reflection->getParameters();
				}

				$args = array();

				foreach ($step['args'] as $i => $arg)
				{
					if (isset($params[$i]))
					{
						// Assign the argument by the parameter name
						$args[$params[$i]->name] = $arg;
					}
					else
					{
						// Assign the argument by number
						$args[$i] = $arg;
					}
				}
			}

			if (isset($step['class']))
			{
				// Class->method() or Class::method()
				$function = $step['class'].$step['type'].$step['function'];
			}

			$output[] = array(
				'function' => $function,
				'args'	   => isset($args)	 ? $args : NULL,
				'file'	   => isset($file)	 ? $file : NULL,
				'line'	   => isset($line)	 ? $line : NULL,
				'source'   => isset($source) ? $source : NULL,
			);

			unset($function, $args, $file, $line, $source);
		}

		return $output;
	}

	/**
	 * General Error Page
	 *
	 * This function takes an error message as input
	 * (either as a string or an array) and displays
	 * it using the specified template.
	 *
	 * @access	private
	 * @param	string	the heading
	 * @param	string	the message
	 * @param	string	the template name
	 * @return	string
	 */
	function show_error($heading, $message, $template = 'error_general', $status_code = 500)
	{
		// If we are in production, then lets dump out now.
		if (IN_PRODUCTION)
		{
			return parent::show_error($heading, $message, $template, $status_code);
		}
		
		if( ! headers_sent())
		{
			set_status_header($status_code);
		}
		$trace = debug_backtrace();
		$file = NULL;
		$line = NULL;
		
		$is_from_app = FALSE;
		if(isset($trace[1]['file']) AND strpos($trace[1]['file'], APPPATH) === 0)
		{
			$is_from_app = !self::is_extension($trace[1]['file']);
		}

		// If the application called show_error, don't output a backtrace, just the error
		if($is_from_app)
		{
			$message = '<p>'.implode('</p><p>', ( ! is_array($message)) ? array($message) : $message).'</p>';

			if (ob_get_level() > $this->ob_level + 1)
			{
				ob_end_flush();	
			}
			ob_start();
			include(APPPATH.'errors/'.$template.EXT);
			$buffer = ob_get_contents();
			ob_end_clean();
			return $buffer;
		}

		$message = implode(' / ', ( ! is_array($message)) ? array($message) : $message);

		// If the system called show_error, so lets find the actual file and line in application/ that caused it.
		foreach($trace as $call)
		{
			if(isset($call['file']) AND strpos($call['file'], APPPATH) === 0 AND !self::is_extension($call['file']))
			{
				$file = $call['file'];
				$line = $call['line'];
				break;
			}
		}
		unset($trace);

		self::exception_handler(new ErrorException($message, E_ERROR, 0, $file, $line));
		return;
	}
	
	/**
	 * Is Extension
	 *
	 * This checks to see if the file path is to a core extension.
	 *
	 * @access	private
	 * @param	string	$file
	 * @return	bool
	 */
	private static function is_extension($file)
	{
		foreach(array('libraries/', 'core/') as $folder)
		{
			if(strpos($file, APPPATH . $folder . config_item('subclass_prefix')) === 0)
			{
				return TRUE;
			}
		}
		return FALSE;
	}
}

/* End of file: MY_Exceptions.php */